Liquid-fuel burner



Jan. 3,' 1928.

Patented Jan. 3, 192a.

UNITED STATES PATENT OFFICE.

JOHN H. MOILVAINE, OF LAKE FOREST, ILLINOIS.

mourn-FUEL BURNER.

Application fl1ed September 8, 1925. Serial No. 54,861.

This invention relates to the burning of liquid fuel in what is commonly known as oil burners for both domestic and commercial purposes. v

The present invention has for its principal object the provision of a novel means for burning liquid fuel continuously at high, low

and intermediate loads as distinguished from some types of burners designed to burn intermittently because of their inherent inability Another purpose of my invention is to overcome certain difficulties inherent in prior oil burners such for example, as the formation of carbon, noise created especially at high loads, improper proportioning and mixing of the air and oil at all loads, flickering out at low load, and blowing out at I high load. In addition to overcoming these objections my improved burner produces a horizontally issuing flame at the higher loads which is desirable especially in installations in heaters and furnaces, as will be described more fully hereinafter.'

In furtherance of the foregoing general objects my invention contemplates the provision of a combustion chamber or fire pot in a vertical position andthe delivery of the oil and air downwardly into the combus- .tion chamber from the top thereof, as distinguished fromthe conventional horizontal combustion chamber having a lateral air and oil inlet. Furthermore, the combustion chamber is shaped to provide a small pocket or auxiliary combustion chamber in which the oil burns at all loads but which is primarily designed for burning at the low load without flickering out and without the formation of carbon to any detrimental degree. The combustion chamber is further shaped to produce a peculiar and novel method of vaporizing the oil and mixing the oil vapor and air so as to secure complete combustion at all loads and to cause the flame to issue from the combustion chamber in a most advantageous manner, all of which will be explained more particularly heremafter. 1

Other objects -and attendant advantages will be appreciated by those skilled in this art as the invention becomes better understood by reference to the following descrip tion when considered in connection with the accompanying drawing, in which- Fig. 1 is a vertical section through a furnace equipped with a liquid fuel burner embodying my invention;

Figs. 2, 3,and 4 are top, side and front views respectively, of the combustion chamher or fire pot; and

Figs. 5, 6, and 7 are diagrammatic views corresponding with Figs. 2, 3, and 4, respectively, illustrating combustion at a low load.

While my invention may be utilized in many different commercial and domestic in-, stallations it is primarily intended for domestic heating purposes where efl'iciency, quiteness, and a wide range of loads are important factors. In the present case I have, therefore, shown the combustion chamber installed in a furnace, this installation being the same as disclosed in my copending application Serial No. 15,448, filed July 23, 1925, which shows a complete apparatus for delivering. air and oil in positively regulated proportions to the combustion chamber. In

this example the fire pot designated generally ,by 8 is supported in an upright position on a base 9 which rests on the furnace grates 11 over which a layer of fire brick 12 is placed. Air is delivered to the fire pot 8 by any suitable means such, for example, as through a pipe 13 from a blower as explained in said copending application. The pipe 13 enters the heater or furnace through the fire door 14 and has a vertical end 15 which sets into the top inlet end 16 of the fire pot. The oil supply is through a pipe 17 which preferably is disposed within the air delivery pipe as described in said copending application and has a vertical end 18 terminating in a sharp delivery point 19 from which the oil may drip in a steady feed into the combustion chamber at an unusually low feed per hour.

The air and oil enter the combustion chamber'through' an inlet opening 21 in the top horizontal wall 22 of the fire pot, this opening being preferably rectangular in crossback and side Walls 23 and 24 is formed a pocket designated generally by 25 which provides an auxiliary or low load combustion chamber. As shown in Fig. 2 the rear wall 26 of this pocketis coplanar with the vertical wall 23 and the opposite wall 27 is of semiconical shape the curvature of which tends from a base plane 28 at the back wall 23 forwardlyto the apex 29 on the side wall 24. The bottom of the combustion chamber is'inclined from the lowest point 31, which is the lowest point in-the pocket 25 directly beneath the side wall 24 as shown in Fig. 4, upwardly away from said pocket at a low, gradual angle providing an inclined portion 32, the purpose of which will be described hereinafter. The side wall 33 opposite the wall 24 is curved in the form of a semiopposite side, wall 24 and in avertical planeas shown in Fig. 3 so as to converge with the top wall 22. I This inclination of .the side wall 33 causes it to merge into the front wall 34 which'in turn follows the general curvature of said side wall 33 and'merges into the opposite side wall 24. The outlet 35 through which the flame issues from the combustion chamber is circularand located at the front of the fire pot tangential to both the top wall 22 and the side wall 24.

In Figs 5,6 and 7 I have shown diagrammatically the operation at the low load,the lightarrows A indicating theincoming air, the heavy dotted lines B the dripping. oil, the heavy arrows C the flame and the light arrows D, the hot ases. It will be noted that the incoming air passing directly down along the side wall 24, impinges against the inclined front wall 34 and bottom 32 and is deflected in part into the pocket 23 where it is caused to whirl or rotate by reason of the shape of said pocket from which it passes into the main combustion chamber in a whirling mass which revolves about a horizontally disposed axis substantially parallel with the back wall as noted by the long heavy arrow in Figs 5. and 7 The remainder of said incoming air passes directly into the main combustion chamber and is caused by the curved and inclined walls thereof to whirl as indicated by the arrows D about an axis indicated by the long li ht arrows in Figs. 5 and 6, it being noted t at the whirling air, or mixture, issuing from the smaller pocket emerges into the whflling air, or

mixture, in the main part of the combustion chamber. The oil which drips slowly and steadily at the low load at the rate of about five per cent or less of. the maximum oil feed impinges on the bottom wall of the combustion chamber which needs to be preheated by. any 'suitable means only when starting the burner. The means for preheating is also utilized for initially igniting the fuel mixture. The .oil dripping on the heated surface 32 is vaporized by contact with the heated surface and mixed with the whirling air in the small pocket so that the fuel burns intensely in this pocket and the flame issues into the main combustion chamber as v illustrated by the heavy arrows in Fig. 7. By reason of this construction, whereby the flame burns in a pocket protected from the main blast of air, it is possible to support thorough, combustion at a remarkably low oil feed per hour which I have termed the low load and which in practice is not in-' tended for heating" the furnace but rather for maintaining a constant flame and for keeping the fire pot heated sufficiently to maintain continuous combustion and to enable the flame to be increased at will or under thermostatic control without the use of a pilot light or ignition means employed in burners which operate intermittently. It will be noted moreparticularly that the oil drips onto the heated inclined bottom wall 32 and runs down this heated surface to the lowest point 31which I have termed the vaporizingpoint. The oil will be vaporized by contact with said heated surface and by action of the air and will be ignited by the flame. At the low load practically all of the oil vapor is'carried into the small pocket or auxiliary combustion chamber and is burned therein. At higher'loads, however, the oil dripping onto the inclined bottoiii'wall. 32 forms a film thereon which is heated by contact therewith and vaporizes. By reason of the inclination of the, lower portion of the front wall 34 and the bottom wall 32 and especially the low angle of the latter the oil film spreads out at the higher loads over a considerable area so that there is contact with the hot metal surface for a period sufli cient to produce vaporization. Another advantage of the inclined bottom wall is that it'always insures flow of oil into the low load pocket regardlessof whetther the fire pot is accurately leveled. At the higher loads the mixture splits into two parts, the

smaller part entering the pocket 25 and burning intensely so as to maintain a comparatively high heat in the vicinity of the vaporizing point, and the larger part following the curvature of the side wall 33 and burning in a whirling or rotating flame. It will be observed that this burning mixture is retarded or held back in the combustion chamber by reason of the inclination and converging relation of the walls 33 and 34 with respect to the op osite walls so that a thorough admixture o the oil vapor and air is effected within the main combus-. tion chamber. The flame burns intensely in a whirling cone finally extending at thefull load a distance from the fire pot, approximately as shown by; the arrows in Fig. 1.

It is believed that the foregoing conveys a clear understanding of the objects prefaced above and while I have illustrated but at single working embodiment it should be understood that changes might be made in adapting the fire pot to different installations without departing from the spirit and scope of the invention as expressed in the appended claims, in whichll, claim: V

l. A. fire pot for burnin liquid fuel having a main combustion c -amber said pot having means for delivering fuel and air into the same to a point at one side of said chamber, and a pocket in which the liquid fuel is adapted to burn at low load, the pocket being alongside the main combustion chamber at the point of fuel and air delivery within the fire pot.

2. A fire pot for burning liquid fuel havinga main combustion chamber, said pot having means for delivering fuel and air in to the same to a point at one side of said. chamber, and an auxiliary combustion chamber, alongside the main chamber at the point of fuel and air delivery within the fire pot, a greater proportion of the fuel being caused to burn in the auxiliary combustion chamber at low load and at higher loads a greater proportion being caused to burn in the main combustion chamber.

3. A fire ot for burningliquid fuel having an opening in its top through which air andliquid fuel are adapted to be delivered downwardly, a bottom surface onto which said air and liquid fuel are adapted to im pinge and which during operation is heated and adapted for vaporizing the liquid fuel, the fire pot being shaped to provide a main and an auxiliary combustion chamber at opposite sides of said surface shaped sothat low load a greater proportion of the mixture passes into and is burned in the auxiliary combustion chamber and the products of combustion pass therefrom into the main combustion chamber and so that as the load increases a proportionately greater amount of the mixture passes into the main combustion chamber for burning therein, the-main combustion chamber'having an outlet openin throu h which the flame or products of c a D I combustion issue 4* A fire pot'for burning liquid fuel having a common air and liquid fuel inlet opening in its top, a main combustion chamber having a side outlet opening from which the flame or products of combustion issue, and a pocket off the main combustion chamber providing an auxiliary combustion chamber for low load combustion, from which auxiliary combustion chamber the flame or products of combustion issue into the main combustion chamber and thence through said outlet opening.

5. A fire pot for burning liquid fuel having a main combustion chamber and an auxiliary and smaller combustion chamber, in the latter of which liquid fuel is adapted to burn at low loads, said combustion chambers being disposed side by side, and means for delivering air and liquid fuel into said fire pot between the two chambers, combustion being caused to take place primarily in the auxiliary combustionchamber at low load and the flame or products of combustion issuing therefrom into the main combustion chamber and as the load increases the flame being crowded out of the auxiliary chamber and burning to a proportionately greater extent in the main combustion chamber.

6. An upright fire pot having a vertical back and a side wall in substantially right angular relation, a substantially horizontal top wall having an inlet opening near the juncture of said back and side walls, a low load pocket formed at the juncture of said back and side walls at the bottom thereof, the bottom wall being inclined upwardly away from the back wall, the side wall oppofor site from said vertical side wall being curved in a vertical plane and inclined forwardly. from the back wall so as to converge with relation to said opposite side wall, and the fire pot having a circular outlet opening at its front substantially tangential to the top wall and the vertical side wall.

7. An upright fire pot having a vertical back and a side wall in substantially right angular relation, a substantially horizontal top wall having an inlet opening near the juncture of said back and side walls, a low load pocket formed at the juncture of said back and side walls at the bottom thereof, the bottom Wall beinginclined upwardly away from the back wall, the side wall opposite from said vertical side wall being curved in a vertical plane and inclined forwardly from the back wall so as to converge with relation to said opposite side all, the fire pot having acircular outlet opening at its frontsubstantially tangential to the top wall and the vertical side wall, said inlet opening being rectangular in crosslsection and spaced forwardly from the back lowest point contiguous to the lowest point in the low load pocket to provide a vaporizing surface from which oil vapor is adapted to enter said pocket at low load but from which an increasingly greater proportion of oil vapor is adapted to be carried into the main combustion chamber as the load increases.

8. An upright fire pot having a vertical back and a side wall in'substantially right angular relation, a substantially horizontal top wall having an inlet opening near the juncture of said back and side walls, a low load pocket formed at the juncture of said back and side wallsat the bottom'thereof, the bottom wall being inclined upwardly away from the back Wall, the side wall opposite from said vertical side wall being curved in a vertical plane and inclined forwardly from the back wall so as to converge with relation to said opposite side wall, the fire pot having a circular outlet opening at its front subtantially tangential to the top wall and the vertical side wall, said low load pocket having a wall substantially semicircular in a vertical plane opposite from said curved side wall and decreasing in depth from the back wall at progressive points forwardly to a point of intersection with the inclined bottom wall and the vertical side wall.

9, A fire pot for burning liquid fuel having a vertical back wall, a vertical side wall at right angles to the back wall, an opposed side wall at an acute angle to the back wall A and curved in a vertical plane, said opposed side wall merging at its top into a horizontal to wall and at itsbottom into a bottom wall w ich inclines downwardly toward the back wall, the chamber having an inlet opening in its top wall and an outlet opening intermediate the top and bottom walls at the side opposite from the back wall.

10. A fire pot as set forth in claim 9, in which the inlet opening is located in the top wall at the juncture of the back wall and the first-mentioned side wall.

11. A fire pot as set forth in claim 9, in cluding a low load pocket in the firstinentioned side wall at the bottom thereof 12. A fire pot as set forth in claim 9, in which the inlet opening is located in the top wall at the juncture of the back wall and the first-mentioned side wall, and including a low load pocket in the said side wall at the bottom thereof adjacent tothe back wall.

13. A firepot for burning liquid fuel having amain combustion chamber one side of which is 'in the form of a semi-section of a cone frustrum and the other side of which has a semi-conical pocket providing a low load combustion chamber.

14. A fire pot for burning liquid fuel having a main combustion chamber and an auxiliary combustion chamber disposed side by side and having fuel and air delivered just between the same, the sides of both chambers being curved to cause the fuel mixture tomove and burn in a whirl, the curvature of the auxiliary chamber being abrupt and that of the main chamber a gradual sweeping curvature, the fuel mixture being arranged to burn in a whirling mass in the auxiliary chamber at a comparatively low load.

15. An upright fire pot having a vertical back and a' side wall in substantially right angular relation, a substantially horizontal top wall having an inlet opening therein, a

low load pocket formed at the juncture of said back and side walls at. the bottom thereof, the bottom wall being inclined upwardly away from the back wall, the side wall opposite from said vertical side wall being curved in a vertical plane and inclined forwardly from the back wall so as to converge with relation to said opposite side wall, and the fire pot having a front flame opening. 4

16. An upright fire pot having a vertical back and a side wall in substantially right angular relation, a substantially horizontal top wall having an inlet opening therein, a low load pocket formed at the juncture of said back and side walls at the bottom thereof, the bottom wall being inclined upwardly away from the back wall, the side wall opposite from said vertical side wall being curved in a vertical plane and inclined forwardly from the back wall so as to converge with relation to said opposite side wall, the fire pot having a front flame opening, said inlet opening being spaced forwardly tlft from the back wall and contiguous to said vertical side wall, and the bottom wall beneath said opening being inclined downwardly with its lowest point contiguous to the lowest point in the low load pocket to provide a vaporizing surface from which oil vaoris adapted to enter said pocket at low load but from which an increasingly greater proportion of oil Vapor is adapted to be carried into the main combustion chamber as the load increases.

17. An upright fire pot having a vertical back and a side wall in substantially right angular relation, a substantially horizontal top wall having an inlet opening therein, a low load pocket formed at the juncture of said back and side walls at the bottom thereof, the bottom wall being inclined Tupwardly away from the back wall, the side wall opposite from said vertical side wall being curved in a vertical plane and inclined forwardly from the back wall so as to converge with relation to said opposite side wall, the fire pot having a front flame opening, said low load pocket having a wall substantially semi-circular in a vertical lane opposite from said curved side .wal but on a smaller radius.

18. A fire pot of the character described, having a vertical back wall and a side wall in substantially right angular relation, a top wall having a fuel and air inlet opening therein, a semi-conical main combustion chamber having the back wall as a base and formed on one side of the side wall in direct communication with the aforesaid inlet opening, the curvature of the walls of said chamber being of relatively ample radius, and an auxiliary'combustion chamber provided on the other side of the side wall having curved walls on a relatively small radius, said chamber being in open communication with the main combustion chamber, and hence indirectly in communication with the aforesaid inlet opening by way of the main combustion chamber.

19. A fire pot as set forth is claim 18, wherein the auxiliary combustion chamber is likewise of semi-conical form with the base thereof at the back wall.

20. A fire pot for burning liquid fuel comprising a main combustion chamber, and an auxiliary combustion chamber formed as a lateral extension of the main combustion chamber, the bottom walls of both of said chambers being inclined toward a common low point, and said pot having means for delivering fuel and air into the same in the vicinity of said low point.

21. A fire pot for burning liquid fuel comprising a main combustion chamber, and an auxiliary combustion chamber formed as a lateral extension of the main combustion chamber, the bottom Walls of said chambers bein inclined toward a common low oint 'whidh marks the separation of the auxiliary chamber from the mainchamber, and said into the same between the two chambers in the vicinity of said low point,

22. A fire pot having a vertical back walland a side wall in substantially right angu lar relation, a main combustion chamber formed on one side of said side wall, and an auxiliary combustion chamber formed on the other side of said side wall opening off the lower end of the main combustion chamber, the bottom Walls of both chambers being inclined toward a common low point at the lower end of said sidewall, and said fire pot having means for delivering liquid fuel and air into said main combustion chamber along the side wall to the vicinity of the low point. 23. A liquid fuel burner fire pot having a main chamber and an ante-chamber openin off the same, the said pot having inlet and outlet openings common to the two chambers for the intake of fuel and air and the outlet of the products of combustion, the main chamber being formed of the pro er size and proportions for high load operatlon, and the ante-chamber being formed of the proper size and proportions for low load operation, the pot having means for delivering fuel and air therein between the two chambers and at J OHN H. MOILVAINE. 

